feat: Add option to disable signal handler

app.go

@@ -256,6 +256,23 @@ func (l loggerOption) String() string {
 	return fmt.Sprintf("fx.Logger(%v)", l.p)
 }
 
+func DisableSignalHandler() Option {
+	return disableSignalHandler{}
+}
+
+type disableSignalHandler struct{}
+
+var _ Option = disableSignalHandler{}
+
+func (disableSignalHandler) apply(m *module) {
+	m.app.receivers.notify = func(c chan<- os.Signal, sig ...os.Signal) {}
+	m.app.receivers.stopNotify = func(c chan<- os.Signal) {}
+}
+
+func (disableSignalHandler) String() string {
+	return "fx.DisableSignalHandler()"
+}
+
 // NopLogger disables the application's log output.
 //
 // Note that this makes some failures difficult to debug,

app_internal_test.go

@@ -21,8 +21,10 @@
 package fx
 
 import (
+	"context"
 	"errors"
 	"fmt"
+	"os"
 	"sync"
 	"testing"
 
@@ -115,3 +117,37 @@ func TestAnnotationError(t *testing.T) {
 	assert.ErrorIs(t, err, wantErr)
 	assert.Contains(t, err.Error(), wantErr.Error())
 }
+
+// TestDisableSignalHandler tests disabling the default signal handler.
+// It's an internal test to allow us replace the app.receivers.notify function.
+func TestDisableSignalHandler(t *testing.T) {
+	for _, disableSignalHandler := range []bool{false, true} {
+		testName := "Not disabling signal handler"
+		if disableSignalHandler {
+			testName = "Disabling signal handler"
+		}
+		t.Run(testName, func(t *testing.T) {
+			app := New()
+			calledNotify := false
+
+			app.receivers.notify = func(c chan<- os.Signal, sig ...os.Signal) {
+				calledNotify = true
+			}
+
+			if disableSignalHandler {
+				opt := DisableSignalHandler()
+				opt.apply(app.root)
+			}
+
+			app.Start(context.Background())
+			app.Stop(context.Background())
+
+			if disableSignalHandler {
+				assert.False(t, calledNotify)
+			} else {
+				assert.True(t, calledNotify)
+			}
+		})
+
+	}
+}